The goal of this thread is to choose a cartridge to match an arm from a complete newbie standpoint.

To make things "easier", let's go with:

- tonearm is SME 309 (thanks Bob Boyer)

- looking at two cartidges; Ortofon 2M Black and audio-technica VM760SLC.

I went with this particular arm and cartridges, simply because there are datasheets available.

Now...Ortofon has the formula to calculate the resonance frequency, I have the data required (arm's effective mass and cartridge compliance), so nothing can be more straightforward...untill I start reading:

- "When selecting either MC or MM cartridges for your record player,

**total effective mass of tonearm (including cartridge and headshell)**has to be taken into account in relation to the mechanical compliance (elasticity) of the cartridge cantilever system."

- "

**M**-

**Total tonearm system mass which is a sum of Mass of cartridge, Mass of headshell and screws and Effective mass of tone arm**(all values in gram).".

PREDICAMENT no. 1

Total effective mass....total tonearm mass...eeeehm?...what now?! OK, let's read-up on effective mass............done and understood - it's about the moment of inertia. Fine?....nope, not by far, if the accuracy level is supposed to be according to stated PI-value (to the ELEVENTH decimal). OK, let's go anal then. You can't just add mass of an object to effective mass! This might be accurate/negligible enough, but I can't tell - remember the PI-value...which leads to

PREDICAMENT no. 2

I can make an educated guess about the effective mass/moment of inertia of the cartridge + mounting screws (with SME 309 the headshell is a part of the arm) with a higher accuracy than simply assuming this mass (with dimension of zero) is concentrated on the tip of the stylus...which leads to

PREDICAMENT no. 3

The effective mass, as stated by SME...based on what position of the counterweight?!

PREDICAMENT no. 4....

Compliance (dynamic) of the audio-technica given at 100Hz (that's why I have chosen it) - how does it translate to 10Hz...and does the formula relate to 0, 10, 100Hz or whatever value?

And so on and so forth.

Take it from here.

Anyways, merry Christmas and a happy new year.

Borut